This invention relates to a die lubricant nozzle for use in can bodymakers and the like, and more particularly, to a die lubricant nozzle of the type surrounding the ram opening of a tool pack axially preceding a die ring thereof and directing lubricant into the tool pack opening for providing lubrication and cooling during metal working operations on cups carried through the die pack by the ram. According to the improvements of the present invention, the die lubricant nozzle directs an annular lubricant flow continuously along and against die ring angled entrance surfaces of an axially adjacent die ring and to the die ring forming surface regardless of the particular position relative to the die ring of the cup being carried by the ram and formed by the die ring. Furthermore, when the cup is not in the die ring and regardless of the relative position of the ram, whether extending through the die ring or completely displaced therefrom, the die lubricant nozzle of the present invention not only directs the annular lubricant flow along and against the die ring angled entrance surfaces to the die ring forming surface, but also over such forming surface and along the die ring angled exit surface as a result of natural adherence of the lubricant to the die ring surfaces.
In a modern can bodymaker, an axially reciprocal ram ready for the start of its working metal forming stroke is positioned totally withdrawn from the bodymaker die pack and a previously blanked and drawn, shallow metallic cup is fed into axial alignment with the ram end portion, the cup opening facing the ram end portion. With the cup so located, the ram moves fully into the cup and begins carrying the same into the entrance of the die pack opening and subsequently through a redraw die ring, if the same is provided, and ultimately through a series of usually two or more axially spaced ironing rings, ultimately exiting the die pack by merely passing through a usual stripper without any stripping action of the cup from the ram. With the ram extending axially completely through the die pack and the cup now of greatly lengthened and thin-walled formation, the ram completes its working metal forming stroke by forcing the cup bottom wall against a doming die surface for finally appropriately metal forming the cup bottom wall into final shape whereupon the ram reverses its axial movement and begins its reverse return stroke.
At initiation of the ram reverse return stroke, the now formed cup in final can body form still remains adhering to the ram end portion so that as the ram returns through the stripper, the now formed cup is engaged by the stripper and retained stationary while the ram continues its return stroke movement to thereby remove the cup from the ram. With the ram continuing its return stroke movement, it withdraws from the die pack through the series of ironing die rings and the redraw die ring ultimately totally withdrawing from the die pack and completing its reverse return stroke by assuming its original position spaced from the entrance of the die pack. The next to be formed shallow cup is then fed into location at the entrance to the die pack, the ram starting its next working metal forming stroke moves into engagement with the cup and the entire cycle is repeated.
To bring these ram reciprocal movement and cup metal forming operations into proper prospective, it is pointed out that a modern can bodymaker operates at speeds in the order of 150 to 175 complete cup metal forming cycles per minute. The metallic cups formed of either aluminum or tin plate in the starting, shallow cup state have wall thicknesses in the order of 13 to 14 thousandths of an inch and in the final wall lengthened state have wall thicknesses in the order of 4 to 5 thousandths of an inch. Thus, it can be very well appreciated that the various metal forming operations performed by the various die rings of the die pack are extremely delicate metal forming operations at high, heat generating speeds requiring efficient die lubricant flow for maximizing lubrication and cooling. Consequently, it is imperative that individual coolant nozzle structures be located in the die pack ahead of at least the individual ironing die rings in view of these ironing die rings being located well internally of the die pack and otherwise quite inaccessible for directing a lubricant flow thereto.
For instance, with the metallic cups being carried through the ironing die rings at the extremely high speeds, lubricant must be constantly present in order that the wall ironing metal working operations can be consistently and uniformly carried out. At the same time, the constant generation of heat from such metal working operations as the result of the ironing die ring and metallic cup surfaces contacting at these high speeds must be dissipated in order that such temperatures will be maintained relatively uniform over a reasonable range so as to maintain uniformity of metal working and uniformity of the final cup products. A still further factor of vital concern is occasioned by build up on the ironing die surfaces and cup surfaces of various forms of extraneous debris, both metallic and otherwise, which can inhibit uniformity and predictability of relatively delicate metal forming operations as are herein involved. The lubricant, therefore, is desired under optimum conditions to be a constantly flowing and overall metal surface covering lubricant, most importantly, constantly present and flowing over surfaces in metal-to-metal contact, in order to perform these combined lubricating, heat dissipating and washing functions.
Various forms of prior die lubricant nozzle constructions attempting to satisfy these optimum conditions have heretofore been provided, one of which having the purpose of directing a continuous, annular flow of lubricant surrounding and against the sidewalls of the cups during their axial movement through a particular ironing die ring. More specifically, the annular coolant flow is directed into the die pack opening spaced axially ahead of the particular ironing die ring so that as the cups are carried axially through the die pack opening by the ram, this annular coolant flow will impinge against the sidewalls of the cups and due to the axial movements of the cups will be carried by the cup surfaces to the ironing die ring metal forming surfaces. One of the principle difficulties with this construction of die lubricant nozzle in attempting to satisfy the foregoing optimum conditions is that, at best, the only time that a constant lubricant flow is maintained over the ironing die ring surfaces, and then only over the exact metal working surfaces thereof, is during the short interval of presence of a cup passing through the ironing die ring. At all other times, whether or not the ram alone is present, the lubricant flow is always spaced from the die ring surfaces and there is not the continuous lubricant flow against these die ring surfaces for heat dissipation and debris washing and removal.
Another prior form of die lubricant nozzle construction has included a series of circumferentially spaced jets positioned around the die pack opening similarly spaced ahead of the particular ironing die ring, but directing jets of coolant diametrically across the tool pack opening at an axial angle sufficient to impinge the jets of coolant against the particular ironing die ring at the diametrically opposite side of the tool pack opening when the cup and ram or the ram alone are not present. When the cup is present, the same moderate lubrication for only the die ring metal working portion is supplied, and when the ram alone is present in either of its working metal forming or reverse return strokes, the lubricant cannot contact the ironing die ring at all, while during the period that the ram is forwardly of the ironing die ring in portions of either of its strokes, the lubricant can pass diametrically across the tool pack opening and impinge against the exposed surfaces of the ironing die ring. Obviously, if the diametrical coolant jets are spaced sufficiently close together, a relatively steady flow of coolant of moderate flow intensity can be supplied to the metal working portion of the ironing die ring during the actual metal working operation as in the previously discussed prior construction, but otherwise there is no heat dissipating and debris washing and removal function accomplished except during the partial cycle short periods of time when the ram is removed from the ironing die ring at the forward portions of these strokes. Thus, some metal working operation lubrication and some heat dissipation and debris washing and removal slightly improved over the above discussed prior construction while still not very closely approaching the optimum desired conditions.